Hole coring system with lever arm

Abstract

A hole coring system for drilling large diameter holes with a handheld tool. The drill bit is guided by a mandrel attached to the concrete and serves as a central guidepost that ensures precise centering of the drill bit. Commonly available tools may be used to rotate the drill bit. A lever arm may be attached to the tool and used to resist any torquing action. Additionally, a brace may be attached to the lever arm which may be used to resist any torquing action.

1. An apparatus for drilling holes in a substrate, the apparatus comprising:
 a mandrel having a distal end portion and a proximal end portion coaxially aligned to the distal end portion, the distal end portion being smooth and cylindrical, the distal end being attachable to the substrate, the proximal end portion being threaded; 
 a hollow tubular drill bit disposed about the distal end portion of the mandrel; 
 a drive shaft fixedly attached to the drill bit and disposed about the mandrel; 
 a bearing mounted within the drive shaft and seated on the distal end portion of the mandrel; 
 an advancement portion which threadably engages the threaded proximal end portion of the mandrel and pushes the drive shaft toward the substrate; 
 a power transmission box having an output sleeve disposable about the drive shaft and an input shaft wherein rotation of the input shaft is operative to rotate the output sleeve; 
 a motor coupleable to the input shaft of the power transmission box and operative to rotate the input shaft; and 
 a lever arm attached to the power transmission box for resisting a reverse torque created by rotation of the drill bit in the substrate. 
 
   
   
     2. The apparatus of  claim 1  wherein a housing of the motor is rotatable with respect to the power transmission box, and the apparatus further comprises a motor brace attachable to the lever arm to restrain rotation of the motor's housing due to the reverse torque created by rotation of the drill bit in the substrate. 
   
   
     3. The apparatus of  claim 2  wherein the motor brace is selectively positionable along a longitudinal length of the lever arm to allow for various sized motors. 
   
   
     4. The apparatus of  claim 1  wherein the lever arm is an elongate rigid bar. 
   
   
     5. The apparatus of  claim 1  further comprising a lever arm brace attachable to the substrate in proximity of the torque arm to restrain rotation of the lever arm due to the reverse torque created by rotation of the drill bit in the substrate. 
   
   
     6. The apparatus of  claim 5  wherein a front surface of the lever arm brace is generally linear and generally parallel to a longitudinal axis of the mandrel to permit the torque arm to slide down the front surface as the drill bit penetrates the substrate. 
   
   
     7. The apparatus of  claim 1  further comprising a rotatable shaft attached to the power transmission box for manually rotating input shaft to assist in coupling the input shaft to a spindle of the motor or for manually rotating the output sleeve to assist in rotating the drill bit in reverse to loosen the drill bit from the substrate when locked together. 
   
   
     8. The apparatus of  claim 1  wherein the motor is a gas powered chop saw or a rotary saw. 
   
   
     9. The apparatus of  claim 1  wherein the advancement portion is a nut. 
   
   
     10. The apparatus of  claim 1  further comprising an elongate collar between the advancement portion and the drive shaft. 
   
   
     11. The apparatus of  claim 10  wherein the elongate collar and the advancement portion are fabricated from a unitary material. 
   
   
     12. The apparatus of  claim 10  wherein the elongate collar and the drive shaft are fabricated from a unitary material. 
   
   
     13. A method of drilling holes in a substrate, the method comprising the steps of:
 attaching a mandrel to the substrate; 
 attaching a drive shaft to a hollow drill bit; 
 disposing the drive shaft and the drill bit about the mandrel; 
 disposing an output sleeve of a power transmission box about the drive shaft such that rotation of the output sleeve rotates the drive shaft and the drill bit; 
 attaching a motor to an input shaft of the power transmission box for rotating the output sleeve; 
 adjusting a lever arm attached to the power transmission box such that the torque arm will contact a lever arm brace, substrate or proximate stationary object for resisting a reverse torque created by rotation of the drill bit in the substrate when the motor is turned on; 
 turning on the motor thereby rotating the input shaft, output power sleeve, drive shaft and the drill bit wherein the drill bit penetrates the substrate; 
 allowing the lever arm to come into contact with the lever arm brace, substrate or proximate stationary object to stop rotation of the lever arm due to the reverse torque created by rotation of the drill bit in the substrate. 
 
   
   
     14. The method of  claim 13  further comprising the step of attaching the lever arm brace proximate to the lever arm. 
   
   
     15. The method of  claim 14  further comprising the step of attaching a motor brace to the lever arm proximate to a housing of the motor to restrain rotation of the motor's housing due to the reverse torque created by rotation of the drill bit in the substrate. 
   
   
     16. The method of  claim 13  further comprising the step of manually rotating a rotatable shaft operative to rotate the input shaft to assist in coupling a spindle of the motor to the input shaft. 
   
   
     17. The method of  claim 13  further comprising the step of manually rotating a rotatable shaft operative to rotate the output sleeve to assist in reversing rotation of the drill bit to loosen the drill bit from the substrate when locked together. 
   
   
     18. An apparatus for drilling holes in a substrate, the apparatus comprising:
 a mandrel having a distal end portion and a proximal end portion coaxially aligned to the distal end portion, the distal end portion being smooth and cylindrical, the distal end being attachable to the substrate, the proximal end portion being threaded; 
 a hollow tubular drill bit disposed about the distal end portion of the mandrel; 
 a drive shaft fixedly attached to the drill bit and disposed about the mandrel; 
 a bearing mounted within the drive shaft and seated on the distal end portion of the mandrel such that the drive shaft and drill bit may rotate about the distal end portion of the mandrel independent from longitudinal traversal of the drill bit and drive shaft along the distal end portion of the mandrel; 
 an advancement portion which threadably engages the threaded proximal end portion of the mandrel and pushes the drive shaft toward the substrate; 
 a power transmission box having an output sleeve disposable about the drive shaft and an input shaft wherein rotation of the input shaft is operative to rotate the output sleeve; 
 a motor having a housing and an output shaft, the motor housing fixedly attached to the power transmission box, the motor shaft coupled to the input shah of the power transmission box and operative to rotate the input shaft.